Discuss the ortho and pyro silicates.

Explanation

Ortho silicate: The simplest which contain discrete `[SiO_(4)]^(4-)` tetrahedral units are called ortho silicates or neso silicates.
Examples: Phenacite `-Be_(2)SiO_(4)(be^(2+)` ions are tetrahedrally surrounded by `O^(2-)` ions) , Olivine- `(Fe//Mg))_(2)SiO_(4)` (`Fe^(2+)` and `Mg^(2+)` cations are octahedrally surrounded by `O^(2-)` ions).
Pyro silicates: Silicates which contain `[Si_(2)O_(4)]^(6-)`
ions are called pyro silicates (or ) Soro silicates.
They are fomed by joining two `[SiO_(4)]^(4-)` tetrahedral units by sharing one oxygen atom at one corner: (one oxygen is removed while joining). Example: Thortveitite `-Sc_(2)Si_(2)O_(7)`